The HIV Prevention Trials Network is holding its annual meeting in Washington, DC this week, and Science Speaks is there, covering Monday, Tuesday and Wednesday sessions.

Can community involvement in HIV testing make an impact on the stigma that has clung to the disease and hindered treatment? Can paying teenage girls to stay in school help keep them from getting HIV? Can a trial determine if earlier and easier access to antiretroviral treatment will help prevent transmission of HIV from injecting drug users who have the virus to their uninfected injection partners? Will a long-acting injectable antiretroviral drug be safe and acceptable for use as pre-exposure prophylaxis to prevent acquiring HIV?

The list of questions goes on and will, for some years to come. Apparently disparate, they are joined by a shared mission under the HIV Prevention Trials Network to find new strategies to prevent the transmission and acquisition of HIV, and to integrate those strategies to ones that have already been proven to work. Strategies already proven to work include the effectiveness of early antiretroviral treatment as prevention of transmission from an infected to an uninfected partner in a committed relationship, of antiretroviral treatment scale-up in lowering community-wide incidence, of antiretroviral treatment in lowering rates of tuberculosis, and of antiretroviral treatment as pre-exposure prevention of acquiring the virus.

Those developments in the last few years are the reason moderator Quarraisha Abdool Karim called now, “the most optimistic time in three decades of the epidemic,” as she opened Monday’s sessions of HPTN’s annual meeting in Washington, DC. Ushering in “the merging of the HIV prevention and treatment agenda” they are discoveries that have added impetus to the age of integrated responses to the HIV epidemic.

The meeting, Dr. Wafaa El-Sadr said in her welcoming remarks, “is like a family get-together.” That may be in part because many of those attending have spent more years inextricably linked through the network of their research than most people not tied by blood are likely to. But the breadth and scope of HPTN research disperses the network across the globe, confronting HIV challenges in Africa, Asia, Europe, and North South and Central America, including the United States, seeking biomedical, behavioral, and structural means of prevention as well methods that integrate the three. Its studies pursue answers among people infected and uninfected with HIV, people recently infected, people infected for years, across a range of populations that includes men who have sex with men, women, people who inject drugs.

Priority populations for the discovery of effective interventions now are young women in sub-Saharan Africa, men who have sex with men in the Americas and in Africa, users of injecting drugs in Asia and Eastern Europe, and discordant couples (couples in which one partner is infected and the other is not), said Dr. Myron Cohen, principal investigator of HPTN 052, which proved the effectiveness of treatment as prevention of HIV transmission from infected to uninfected partners in committed relationships. The focus on those populations is not to the exclusion of other populations, Cohen added, but are a focus at the meeting because of the potential for effective interventions among them to have a wide public health impact.

“Urgency and success,” Cohen said, make integration of proven methods critical, and antiretroviral treatment, he said, has become central to turning the trajectory of the AIDS epidemic now. “It’s a tool we can deploy now, not ten years from now.”

If the quest for answers has seemed epic over the two decades since HPTN predecessor HIVNET began in 1993, Cohen suggested it also is “biblical.”

“One thing begets another,” he said.

“Can HPTN contribute weight to reaching a tipping point?” he asked, apologizing for using a cliche. The tipping point, he meant, he added, is “from discovery to policy change.”